Unit B Chapter 2
Ways in Which Organisms Compete
I. Competition for Limited Resources
A. Food is a resource
1. Animals get it differently
2. Ecosystems have limited supplies
3. Competition (a contest) among organisms
i. Body color helps with survival
ii. Camouflage – body color that
helps organisms hide from
iii. Predator – An organism that
preys on a consumer
iv. Prey – A producer that is
consumed by a predator
i. Needed by all organisms
d. Plants compete for resources also
e. Adaptations help with competition
f. Organisms share resources
i. Compete in different ways
ii. Some hunt in packs
iii. Some hunt individually
g. An ecosystem must be kept in
Question – What are two resources that organisms
may compete for?
Answer – Organisms may compete for food, water,
sunlight, and shelter.
II. Sharing Resources
A. Many organisms share an ecosystem
B. These organisms do not have to compete
1. Occupy their own niche in the
2. Some organisms aid other organisms in
finding a habitat
Question – Why don’t warblers compete for food,
even though they all eat insects in the
Answer – Warblers do not compete for their foods
because they feed at different levels of the
tree. They have a different “niche.”
A. Symbiosis – A long term relationship between
two different organisms
1. It can benefit one, or both, organisms
B. Different organisms often live closely together
for most of their lives in the same niche.
C. Mutualism – A relationship where both
organisms receive benefit(s)
1. Organisms can be plant or animal
Question – What is symbiosis?
Answer – Symbiosis is a long term relationship
between different kinds organisms that is
beneficial to all.
IV. Instincts and Learned Behaviors
A. Behaviors –
1. Instinct – Behavior that an organism
a. It is not unique to the
b. Behavior shared
i. By that entire population
ii. Or by males or females
of the population
2. Learned Behavior – A behavior that
they have learned from their parents
a. Not inherited
b. Mainly used for survival
c. Domesticated animals have
many learned behaviors that
are not necessary for survival
Question – What is the difference between an
instinct and a learned behavior?
Answer – An instinct is inherited, you are born with
it, and a learned behavior is not, it is
taught to you.
A. Organisms may compete for limited resources
in an ecosystem
B. The sizes of certain populations are limited by
the amount of resources available
C. Sometimes organisms share resources
D. Sometimes they form relationships with other
E. Instincts –
2. Learned behaviors
3. Help organisms survive
1. Question – Why does a female sea turtle lay
more than a thousand eggs at a time?
2. Question – How might the number of oak
trees in a park affect the number of squirrels
that can live there?
3. Question - What resources are sometimes
shared by squirrels and certain birds?
4. Critical Thinking – Think of an animal that
lives in your area. What behaviors does it
have for survival?
5. Test Prep – Which of the following is not a
survival instinct for birds?
a. Building nests
c. Eating insects
d. Learning to talk